Ensuring service continuity of a mobile user is a basic function of a cellular mobile communication system, and handover of a serving cell of a mobile station is main means of ensuring the service continuity. In order to facilitate handover of UE (User Equipment), the system needs to configure neighboring relationship for each cell, so that the network side notifies the user equipment of neighbor cell information. The user equipment measures neighbor cells according to the neighbor cell information and then reports a measurement result. The network side then instructs the user equipment to hand over to a certain neighbor cell according to the reported measurement result.
Which neighbor cells are around a certain cell is not only related to a cell distance, but also closely related to a wireless environment where the cell is. Because the wireless environment is complicated, it is very difficult to determine exactly which neighbor cells should be configured for a certain cell at the beginning of network planning, especially in a city environment with dense high buildings. Some other situations will cause that the neighbor cell information is not updated in time, for example, one cell is newly added in the system or an attribute of a cell changes, but the neighboring relationship of the cell is not updated in time, or there is change of environment or omission of a network planner. Thus, the user equipment will not be able to hand over to another cell in time, and the following situations may occur: the load of the current cell will be too high, the signal quality of the current cell becomes worse, the interference is serious or user call drops may occur, and so on. Hence, an ANR (Automatic Neighboring Relationship Function) task is introduced in the 3GPP (3rd Generation partnership project) conference, but there is still no specific procedure about how to control UE to take and report measurements.